1. Field of the Invention
The present invention relates to an apparatus for controlling automatic focusing in continuous photographing cameras.
2. Related Background Art
In general, in automatic focusing cameras wherein a camera lens is shifted by means of a motor to a best focus position in response to an object distance, "out of focus" is prevented by permitting release after the focusing operation has been completed. When the continuous photographing is performed by the use of such automatic focusing camera, a shot speed cannot be maintained constant, since such shot speed varies in dependence upon contrast and/or brightness of an object to be photographed. In this connection, to alleviate the above disadvantage when a constant shot speed is requested, an automatic focusing camera wherein a second shot, a third shot and the like are effected while maintaining the best focus position for a first shot has been proposed.
In this case, although there is no problem when a stationary object is photographed by means of a camera situated in a fixed position, there arises a problem that "out of focus" is generated when the object is continuously moving and/or the camera position is varied.
In order to solve such problem, there has been proposed an automatic focusing camera wherein a predetermined time interval (from when a film has been wound up for the next shot) is pre-set for detecting the best focus position, a focus detecting operation and the shifting of the camera lens to the best focus position are effected within the predetermined time interval, and the release is permitted after the predetermined time interval elapses.
According to such automatic focusing camera, even when the object is moving and/or the camera position is varied, the possibility of "out of focus" is reduced in comparison with the first-mentioned proposed automatic focusing camera. However, in this automatic focusing camera, there arises another problem that the shot speed decreases by an amount corresponding to the above-mentioned predetermined time interval.